Penicillins are conventionally prepared by microbial synthesis in a nutrient medium containing a source of carbon and energy, a source of nitrogen as well as other ingredients such as inorganic salts and precursors. Various media have been successfully employed for this purpose in which the source of carbon and energy is a mixture of cornsteep liquor and carbohydrates such as lactose, glucose, dextrin and starch (see Perlman, "Chemically Defined Media For Antibiotic Production," Ann. N.Y. Acad. Sci., Vol. 139 (1), p. 258-269 (1966)). Other materials reported as successful carbon sources include sucrose, molasses, sorbitol, maltose, fructose, starch hydrolysate, and organic acids such as acetic and lactic.
Ethanol has previously been employed as the major source of carbon and energy in the fermentative production of various amino acids, for example, U.S. Pat. No. 3,563,857 to Oki et al. directed to the production of L-glutamic acid, U.S. Pat. No. 3,595,751 to Nakayama et al. directed to the production of L-lysine, U.S. Pat. No. 3,843,441 to Kubota et al. directed to the production of L-serine, and French Pat. No. 2,048,897 to Ajinomoto Co. directed to the production of L-threonine. Ethanol has also been employed in conjunction with the conventional carbohydrate carbon and energy sources listed above in the fermentative production of organic acids such as citric in U.S. Pat. No. 2,674,561 to Moyer. However, ethanol has not been previously reported as utilizable in the production of penicillins. In fact, ethanol has been stated to be unsuitable as a carbon and energy source in the production of the antibiotics actinomycin (Katz et al., "The Role of Nutrition in the Synthesis of Actinomycin," Applied Microbiology, Vol. 6, p. 236-241 (1958) and neomycin (Majumdar et al., "Utilization of Carbon and Nitrogen-containing Compounds for Neomycin Production by Streptomyces fradiae," Applied Microbiology, Vol. 15, p. 744-749, (1967)).